This invention relates to disk drive arrays.
A disk drive is a data storage device in which data is stored magnetically on a rotatable disk. The invention is particularly concerned with fixed disk drives; that is, with drives in which the disk is not removable in normal operation.
Disk drive units are conventionally packaged in one of a number of standard form factors, to allow them to fit into standard slots of a computer system. For example, one standard configuration uses disk of 5.25 inches (133 mm) diameter, packaged in a housing of dimensions 3.25.times.5.75.times.8 inches (83.times.146.times.203 mm).
It is known to connect a number of separate disk drives (typically multiples of 5) together to form a resilient disk array which can tolerate failure of any one disk by storing data in a redundant manner (e.g. as groups of 4 data bits plus one parity bit).
The object of the present invention is to provide a new configuration for such a resilient disk array.